Hot-gas engine

ABSTRACT

A hot-gas engine comprising a number of cooler-regenerator units which constitute the communication between the heater and the compression space and which each comprise a regenerator, a cooler and a flow guide which are connected together by soldered joints; an O-ring is present between the cooler and the housing in a groove, and another O-ring is present at the area of the communication of the flow guide with the housing. A force is exerted on the assembly of cooler, regenerator and flow guide via an oblique surface to preclude the occurrence of gaps at the area of the O-rings.

PATENTE EEC 31974 saw 10F 2 HOT-GAS ENGINE This is a continuation, of application Ser. No. 273,342, filed July 19, 1972, now abandoned.

BACKGROUND OF THE INVENTION The invention relates to a hot-gas engine comprising a variable space of higher average temperature which communicates with a variable space of lower average temperature; a communication between said spaces comprises a heater and number of cooler-regenerator units, each comprising a housing in which a regenerator, a cooler and a flow-guide. The housing on the regenerator side communicates with the heater and on the flow guide side communicates with the space of lower average temperature.

A hot-gas engine of the above-described type is known from Us. Pat. No. 3,166,91 I. In this known engine, the cooler-regenerator units are constituted by a housing in which the regenerator, cooler and flow guide are incorporated.

In order to be able to dismantle there units, which may be necessary, for example, for cleaning purposes of the regenerator, the regenerator, cooler and flow guide are not rigidly secured to the housing, and two O ring seals to prevent leakage of working medium are present between the cooler and thehousing, and one O-ring seal is present between the flow guide and the housing. The danger exists that the O-rings are squeezed in the narrow gap between the cooler and the housing and between the flow guide and the housing, respectively. In order to keep said gaps small, narrow tolerances are necessary which in turn give rise to difficulties when the housings slightly deform whenthey are soldered to the remainder of the engine. When using higher average pressures in the hot-gas engine, the above-mentioned problems increase of course because as a result of this again larger gaps tend to be formed.

It is the object of the invention to provide a hot-gas engine in which the above mentioned drawbacks are avoided. For that purpose, according to the invention, the hot-gas engine is characterized in that the regenerator, the cooler and the flow guide are connected together by soldered joints; an O-ring seal is present between the-cooler and the housing and isincorporated in a groove in the cooler housing this groove is bounded, on its side facing the flow guide, by a surface of the cooler which engages a surface present on the housing. An O-ring seal is also present at the area of the communication of the flow guide with the side-wall of the housing. The flow guide comprises, on its side facing the cooler, an edge which cooperates with an oblique surface of a cam which forms part of a sliding member which is axially movable inthe housing and which engages, on its side facing the flow guide, a pressure nut which can be screwed in the housing.

By soldering the regenerator, cooler and flow guide together, only one seal along the circumference of the cooler is necessary and one seal at the area where the flow guide communicates with the side wall of the housing. By pressing the sliding member against the flow guide, by means of the nut, the flow guide, as a result of the oblique surface, is forced tightly against the side wall of the housing so that no gap can occur at the area of the O-ring. The assembly of regenerator, cooler and flow guide is also pressed in the axial direction, as a result of which the surface of the cooler which also bounds the O-ring is rigidly forced against the cooperating surface of the housing so'that at that area also no possibility of gap formation exists. This means that a good life of the two O-ring seals is ensured, while nevertheless the assembly need not meet particularly stringent requirements as to accuracy, which, of course, saves cost. Furthermore, an easy dismantlability is ensured. The invention will be described in greater detail with reference to the drawing.

BRIEF DESCRIPTION OF THE DRAWINGS FIGS. 1 and 2 are two diagrammatic sectional views mutually at right angles and not to sale of a part of a hot-gas engine.

FIG. 3 is a diagrammatic sectional view of a coolerregenerator unit of the hot-gas engine shown in FIGS. 1 and 2.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to FIG. 1, reference numeral 1 denotes a cylinder in which a piston 2 and a displacer 3 reciprocate. The piston 2 and the displacer 3 are connected by a piston rod 4 and displacer rod 5, respectively, to a driving mechanism not shown which causes the piston 2 and the displacer 3 to move with a mutual phase difference. A compression space 6 is present between the piston 2 and the displacer 3, while above the displacer 3 an expansion space 7 is present. The expansion space 7 communicates with the compression space 6 via a heater 8 and a number of cooler-regenerator units 9. The heater consists of a number of pipes 10 A cooler-regenerator is shown in greater detail in FIG. 3. Incorporated in a housing 14 is a regenerator 15 which consists of a filling mass 19 and a regenerator housing 20 surrounding said filling mass. Atthe area 21, said housing 20 is connected to the housing 22 of the cooler 16 by a soldered joint. Incorporated in the terminating plates of housing 22 are a number of pipes 23 through which the working medium can flow. Furthermore communicating with the housing are an inlet and an outlet for cooling water of which only one (24, that one on the rear side) is shown in the drawing and through which cooling water flows around the outside of the pipes 23.

An O-ring 26 is incorporated in a groove 25 in the cooler housing 22, groove 25 being bounded on the side of the O-ring 26 facing the flow guide by a surface 27 which engages a surface 28 of the housing 14.

At the area 29 the cooler housing 22 is soldered to the flow guide 17. Said flow guide comprises a duct 30 of such a shape that it communicates at one end with the cooler pipes 23 and at the other end with the duct 18 which constitutes the communication with the compression space. An O-ring seal 40 ensures the seal between the flow guide 17 and the housing 14. An edge 31 of the flow guide 17 engages an oblique surface 32 of a cam 33 which forms part of a sliding member 34 which is movable in the housing 14. The sliding member 34 engages a nut 35.

In this manner a simple and readily operating coolerregnerator unit is obtained in which, since the regenerator 15, cooler 16 and flow guide 17 are connected together by soldered joints, only one O-ring seal 26 is necessary to check leakage of medium between the said elements and the housing 14. Furthermore, only one O-ring seal 40 is necessary at the separation of flow guide and housing wall. By tightening the nut 35, the flow guide is readily forced to the left against the inner wall of the housing 14 via the oblique surface 32 and the combination flow guide-cooler-regenerator is furthermore forced upwards, the surface 27 of the cooler being rigidly forced against the surface 28 of the housing 14. In this manner, no gap formation can occur at the area of the O-ring seals 40 and 26, as a result of which the danger thus does not exist that the O-rings are forced into the gaps. Furthermore, the resulting cooler-regenerator-unit is easy to mantle and dismantle.

Also in the case the housing 14 is non-circular and in the case of wide fits, there still exists no danger for the O-rings 26 and 40 which are loaded by high-pressure to be forced into a gap because at that area the gap is positively kept tight. A further advantage of the coolerregenerator unit according to the invention is that the dead space therein is minimized.

What is claimed is:

I. A hot-gas engine comprising a variable space of higher average temperature which communicates with a variable space of lower average temperature, the communication between said spaces comprising a heater and a number of cooler-regenerator units each comprising a housing in which a regenerator, a cooler and a flow guide are present, the housing communicating, on the regenerator side, with the heater and, on the flow guide side, with the space of lower average temperature, characterized in that the regenerator, the cooler and the flow guide are connected together by soldered joints, an O-ring seal being present between housing, an O-ring seal being also present at the area of the communication of the flow guide with the side wall of the housing, the flow guide comprising, on its side facing the cooler, an edge which co-operates with an oblique surface of a cam which forms part of a sliding member which is axially movable in the housing and which engages, on its side facing the flow guide, a pressure nut screwed into the housing.

2. In a hot-gas engine including first and second variable volume spaces of higher and lower average temperature respectively and a heater, the improvement in combination therewith of at least one coolerregenerator sub-assembly Comprising a housing defining therein a cylindrical bore with top and bottom parts and first and second flow apertures at the top and on the side respectively, a regenerator, a cooler, and a flow guide aligned generally coaxially and soldered together to form a unit with a continuous flow path therethrough having first and second ends for communication with said first and second flow apertures respectively, this unit being removably insertable into said bore through said bottom part thereof, and when inserted the units cooler and the housing having a first set of adjacent contacting surfaces, and the units flow guide and the housings side wall having a second set of adjacent contacting surfaces, the sub-assembly further comprising pressure means for urging said unit axially toward said top part and thereby urging said first set of surfaces tightly together, and simultaneously urging said unit laterally and thereby urging said second set of surfaces tightly together, each of said sets of surface including a recess therein and an O-ring seal in said recess, providing a seal between the surfaces of each set.

3. Apparatus according to claim 2 wherein said pressure means comprises a first pressure surface on said flow guide and a pressure member movable axially relative to the bore and having a second pressure surface oblique relative to said bore axis which second surface contacts said first pressure surface and applies pressure thereto both axially and laterally.

4. Apparatus according to claim 2 further comprising a plurality of said sub-assemblies spaced around the engine.

fg gg UNITED STATES PATENT OFF ICE CERTIFICATE OF CORRECTION- p 3,851,472 Dated December 3,1974

lnventorw GREGORIUS THEODORUS MARIA NEELEN It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:-

I In the Title: Foreign Application Priority Data" I .1

Q "ll887/7l' should be -7 lll887,--

Col. 1, line l3, after "heater" insert Col. 4, lihe 25 "ur l its" 1 shotlld he -r1 nit's-- line- "'housings" should be housin g' s-- "Signed and sealed this 4th day of March 1975- (SEAL) Attest:

o C. MARSHALL DANN RUTH C. MASON Commissioner of Patents Attesting Officer and Trademarks 

1. A hot-gas engine comprising a variable space of higher average temperature which communicates with a variable space of lower average temperature, the communication between said spaces comprising a heater and a number of cooler-regenerator units each comprising a housing in which a regenerator, a cooler and a flow guide are present, the housing communicating, on the regenerator side, with the heater and, on the flow guide side, with the space of lower average temperature, characterized in that the regenerator, the cooler and the flow guide are connected together by soldered joints, an O-ring seal being present between the cooler and the housing and being incorporated in a groove in the cooler housing, said groove being bounded, on its side facing the flow guide, by a surface of the cooler which engages a surface present on the housing, an O-ring seal being also present at the area of the communication of the flow guide with the side wall of the housing, the flow guide comprising, on its side facing the cooler, an edge which co-operates with an oblique surface of a cam which forms part of a sliding member which is axially movable in the housing and which engages, on its side facing the flow guide, a pressure nut screwed into the housing.
 2. In a hot-gas engine including first and second variable volume spaces of higher and lower average temperature respectively and a heater, the improvement in combination therewith of at least one cooler-regenerator sub-assembly comprising a housing defining therein a cylindrical bore with top and bottom parts and first and second flow apertures at the top and on the side respectively, a regenerator, a cooler, and a flow guide aligned generally coaxially and soldered together to form a unit with a continuous flow path therethrough having first and second ends for communication with said first and second flow apertures respectively, this unit being removably insertable into said bore through said bottom part thereof, and when inserted the unit''s cooler and the housing having a first set of adjacent contacting surfaces, and the units flow guide and the housings side wall having a second set of adjacent contacting surfaces, the sub-assembly further comprising pressure means for urging said unit axially toward said top part and thereby urging said first set of surfaces tightly together, and simultaneously urging said unit laterally and thereby urging said second set of surfaces tightly together, each of said sets of surface including a recess therein and an O-ring seal in said recess, providing a seal between the surfaces of each set.
 3. Apparatus according to claim 2 wherein said pressure means comprises a fiRst pressure surface on said flow guide and a pressure member movable axially relative to the bore and having a second pressure surface oblique relative to said bore axis which second surface contacts said first pressure surface and applies pressure thereto both axially and laterally.
 4. Apparatus according to claim 2 further comprising a plurality of said sub-assemblies spaced around the engine. 